In a technique called extract transform load (ETL), data accumulated in an information source system is extracted, the extracted data is transformed into data in a specific format, and the transformed data is loaded in a storage destination system (for example, data warehouse). This series of processes is referred to information integration.
Related art techniques of information integration are available as described below. For example, transform processes are performed on source data via a plurality of transform objects. The data is finally mapped to a target system. The transform process is performed on prepared metadata in accordance with each transform object.
Japanese Unexamined Patent Application Publication No. 11-25126 describes a technique that reduces a cost for building a data warehouse by preparing a mapping table when data is transferred from an existing system to the data warehouse. According to an item name of the existing system as a key, the mapping table specifies (1) an item name and a data format the item is to take in a table of a database in the data warehouse, and (2) a transform logic needed to transfer the item.
Japanese Unexamined Patent Application Publication No. 2004-30179 discloses a technique that speeds up an access process to schema information. The schema information of a database is collected and retained. The retained schema information is compared with schema information acquired again in response to an instruction from a user to obtain difference data.
The above-described techniques of the information integration system do not account for a modification in schema in the information source. If a modification takes place, data transform is not appropriately performed. In a related art technique, an administrator re-produces a logic for data transform. Such a manner leads to an increase in operation costs.